Pump or motor



April 23, 1935. w. FERRIS 1,998,984

PUMP OR MOTOR Filed Nov. 2'7, 1953 5 Sheets-Sheet 1 INVENTOR WALTER FERHIS.

ATTORNEY April 23, 1935.

w. FERRIS PUMP OR MOTOR Filed Nov. 27, 1935 5 Sheets-Sheet 2 lNVENTOR VVALTER FERR'IS.

ATTORNEY April 23, 1935. w. FERRIS 1,998,984

PUMP OR MOTOR I Fi1ed Nov. 2'7, 1935 5 Sheets-Sheet 5 NAM R FERRIS. BY W ATTORN EY April 23, 1935.

wv FERRIS PUMP OR MOTOR Filed Nov. 27, 195 5 5 Sheets-Sheet 4 INVE TOR VVALTEFQ EFR'FQIS. BY

ATTORNEY W. FERRIS PUMP OR MOTOR April 23, 1935.

Filed Nov. 27, 195;; 5 Sheets-Sheet 5 sect/on 5 Sect/oh 4 Sect/ on, 2

5 n m t C e 5 INVENTOR WALTER FERRIS.

ATTORNEY Patented Apr. 23 1935 UNITED STATES PAT-TENT OFFICE tion of Wisconsin Application November 2'7, 1933, Serial No. 699,847

' 20 Claims.

This invention relates to hydraulic machines of the type having radial pistons and cylinders arranged in a cylinder barrel which rotates upon a central valve orpintle through which liquid flows to and from the cylinders, such as the hydraulic machine disclosed in my copending application, Serial O- 2 filed March 23, 1933 of which this application is a continuation as to matters common to both applications.

The machine will function as a pump whenever its cylinder barrel is driven from a suitable source of power and it will function as a motor whenever liquid is delivered under pressure to its cylinders. For the purpose of explanation, the machine will be described herein as a pump but it is to be understood that the invention is equallyapplicable to a motor and that the term pump as used herein is intended to define either a pump or a motor. v v

The central valve or pintle has intake and discharge passages formed therein and terminating,

respectively, in an intake port and a discharge.

port which are ordinarily arranged diametrically opposite each other andseparated by a narrow section generally designated as a "bridge. Each cylinder communicates with these two ports alternately as the cylinder barrel rotates and is open to each port through a substantial part of a half revolution of the cylinder barrel.

When a pump is delivering liquid under pressure, a cylinder passing from the intake to the discharge-port is substantially filled with liquid at a low pressure and, as it begins to pass off the bridge and to open to the discharge port, the pressure of the liquid in the cylinder is suddenly raised-by the high pressure in the discharge port, thereby suddenly loading the piston and its driving mechanism and producing a shock and a resultant noise.

Conversely, when a cylinder passes from the discharge port to the intake port, it contains liquid under high pressure and, as it begins to pass oif the bridge andto open to the intake port, the pressure in the cylinder and the strain upon the piston and its driving mechanism are suddenly released, thereby producing a shock and a resultant noise.

These shocks, caused by each cylinder opening to the intake and' discharge ports, react upon the pintle at its bridge and produce what are generally known as bridge reactions. If a pump is provided with an even number of equally spaced 7 cylinders, one cylinder will open to one port at the two cylinders opening at the same time will be simultaneous and in the same direction.

In order to reduce the bridge reactions and the resultant noise, it has been common practice to provide a'p'ump with an odd number of equally spaced cylinders so that but one cylinder opens to a port at any given instant.

When a pump has been developed which is reasonably quiet at a given maximum pressure and a given maximum speed, a pump of larger capacity may be produced either by increasing the diameter of the cylinders or by providing the pump with more cylinders of the same diameter. The first method increases the shock and noise proportionately to the square of the cylinder diameter and the second method has a similar effect if two or more of the cylinders open to aport at the same instant.

The presentinvention has as an object to provide a pump which will operate quietly and in which the bridge reactions have been reduced to a minimum.

Another object is to provide a 'pump which may be made in larger sizes or capacities without materially increasing either the bridge reaction or the resultant noise. I

Another object is to provide a pump having a large capacity relative to its overall dimensions.

Another object is to provide a pump in which the internal leakage or slip is kept at a substantially constant minimum.

Another object is to provide a pump which is compact and eflicient. 1

Other objects and advantages will appear from the description hereinafter given of a pump in which the invention is embodied.

According to the invention-in one of its aspects, the pump is provided with a plurality of cylinders which communicate with the pintle ports through cylinder ports, a plurality of cylinder ports open successively to one pintle port and then another plurality of cylinder ports open successivelyto the other pintle port, and no two cylinder ports open at the same instant.

According to the invention in another aspect, the pump is provided with a cylinder barrel which rotates upon a taperedpintle and is urged toward the large end thereof by the lateral components of the pumping forces.

The invention is exemplified by the pump illustrated inthe accompanying drawings in which the views are as follows:

Fig. 1 is a longitudinal section taken through the pump on the irregular line l-l of Figs. 2

tudinal rows for the purpose of illustration.

Fig. 1 is a view taken in the same plane as Fig. 1 but drawn to a larger scale.

Fig. 2 is atransverse section taken on the line 2-2 of Fig. 1.

Fig. 3 is adeveloped view of the inside of the cylinder barrel and shows the relation of the cylinder ports to the cylinders and to each other.

Fig. 4 is 'a schematic developed view of the outside of the central valve or pintle and shows the relation of the cylinder ports to each other-and to the pintle ports.

Fig. 5 is a view similar to Fig. 4 but showing only two circumferential rows of cylinder ports.

The pump has its mechanism arranged within and carried by a closed casing I 0 which has a removable head I I attached to its front end and a boss I2 formed integral with its rear head or wall.

The boss I2 supports a valve shaft or pintle B which has its rear part rigidly secured in the boss I2 and its front part tapered and extending forward in the casing.

A cylinder, barrel I4 is journaled upon the tapered part of the'pintle I3 and provided with a plurality of radial cylinders I5 each of which has a piston I6 fitted therein.

Liquid flows to and from the cylinders I5 through two upper passages I! and two lower passages I8 which are formed in the pintle I3 longitudinally thereof and communicate, respectively, at the front ends thereof with an upper pintle port I9 and a lower pintle port 20.

The passages I1 and I8 may be connected-at the rear ends thereof to an external circuit as by means of two pipes 2I and 22 attached to the boss I2 and communicating respectively, with the passages I1 and I8 through two passages 23 and, 24 formed in the boss I 2. I

Each of the pintle ports I9 and 20 may consist of two or more slots. As shown, the port l9 consists of two slots I9 and I9 and the port 28 consists of two slots 21! and 20 which are arranged, respectively, diametrically opposite the slots Ill and I9".

Each of these slots extends from the periphery of the pintle 'into communication with the pintle passages I! or I8 and is formed by removing from the pintle a segment thereof equal to a substantial part of one-half of the cross-sectional area of the pintle at that point.

The ports I9 and 20 are thus separated from each other by a section of metal the outer peripheral surfaces of which are generally known as bridges and which have been designated in Figs. 4 and 5 by the reference numerals 25 and 25 The pump shown is provided with a large number of small cylinders arranged in seven circumferential rows A, B, C, D, E, F, G and discharging through cylinder ports which are arranged in four circumferential rows as shown in Fig. 3 and as will be described hereafter.

The cylinder ports in two of these rows communicate with the slots I9 and 20 alternately and the cylinder ports in the other two rows communicate with the slots I 9 and 20 alternately as the cylinder barrel rotates.

This arrangement avoids ducts of excessive length leading from the end rows of cylinders as would be necessary if each of the pintle ports consisted of a single slot and all of the cylinders communicated therewith during rotation of the cylinder barrel.

Also, such long ducts would contain relatively large volumes of liquid which would be com- 1,998,984 and 3 and showing the pistons arranged in longipressed by the pistons but not expelled into the discharge port of the pintle, and the compression of these volumes of liquid and the following reexpansion thereof when the cylinder ports opened to the intake port would reduce the efficiency of-the pump.

Further,'it would be impossible to provide long ducts leading from cylinders in outside rows and under cylinders in intermediate rows to a central port without materially increasing the distance from the surface of the pintle to the bottoms of the cylinders, thereby increasing the diameters of the cylinder barrel and the pump and further increasing the volume of liquid which is compressed but not ejected into the pintle discharge port.

When the pump is operating, liquid seeps from the high pressure pintle port between the cylinder barrel and the pintle and forms therebetween a lubricating filmthe pressure of which varies in accordance with variations in pump pressure and diminishes as the distance from the high pressure port increases.

The pressure in the lubricating film tends ta separate the cylinder barrel from the high pres sureside of the pintle and thereby tends to cause it to bear more heavily upon the low pressure side of the pintle.

In order to limit the high pressure area in the lubricating film, the pintle is provided with four limit grooves 26, 21, 28 and 29 which extend around the pintle adjacent the ends of the pintle port slots, the slots I9 and 20 being arranged between the grooves 26 and 21 and the slots I9 and 20 being arranged between the grooves 28 and 29.

The area between the grooves 26 and .21 and the area between the grooves 28 and 29 constitute narrow valve seats upon which the lubricating film adjacent thehigh pressure pintle port has a high pressure whenever the pump is delivering liquid at high pressure. 1

The valve seats, or high pressure areas between the grooves 26 and Hand between the grooves 28 and 29, are made relatively narrow so that the outward force exerted by the film upon the cylinder barrel and tending to separate it from the high pressure side of the pintle does not exceed the inward'force which is transmitted from the pistons to the cylinder barrel through the 7 liquid in the cylinders, thereby preventing the .the ends of the cylinder barrel.

The film covering the area between the grooves 21 and 28 is also kept at a low pressure as by connecting the grooves 21 and 28 to each other by a longitudinal groove 30 and draining this area through a small drain channel 3| which extends axially inward from the front end of the pintle and then radially outward into communication with the groove 28.

These low pressure areas function primarily as bearing surfaces which are adequately lubricated by liquid which escapes from the high pressure pintle port and passes the limit grooves.

The cylinder barrel is rotated upon the pintle I3 by a drive shaft 32 which has a circular driver 33 splined upon its inner or rear end. The drive shaft 32 extends throughthe front head II in which it is supported by a ball bearing 34 and the end of the driver 33.

The driver 33 is connected to the cylinder bar rel I4 byflexible driving connections such as a plurality of helical springs 36 which are arranged in suitable recesses formed in the driver and in the cylinder barrel. The springs 36 are capable of transmitting a high driving torque from the driver to the cylinder barrel and will deflect to compensate for slight misalinement of parts and thereby allow the cylinder barrel to be accurately seated upon the pintle.

In order to facilitate manufacturing, the cylinder barrel ordinarily consists of two sections rigidly secured to each other, the outer section 4 having the cylinders formed therein and the inner section having the. cylinderports formed therein. The inner section is ordinarily provided on its inside with a thin liner of bearing metal, such as bronze, but this'charaoteristic has not been illustrated as the use of such metals in bearings is well known.

As previously explained, the cylinders l5 are arranged in circumferential rows, that is, rows which extend around the cylinder barrel in planes transverse to the pintle axis, and the cylinders communicate with cylinderports which are also arranged in circumferential rows.

The pump shown has its cylinders arranged in seven rows A,'B, C, D, E, F, G (Figs. 1 and 3) and with twenty cylinders in each row or a total of 140 cylinders which communicate with twenty cylinder ports which are arranged in four circumferential rows.

The outer (Fig. 3) or rear (Fig. 1 row contains five ports 31 each of which serves four cylinders in row A and four cylinders in row B, the next row contains five ports 38 each of which serves four cylinders in row C and four cylinders in row D, the next row contains five ports 39 each of which serves four. cylinders in. row E and two cylinders front row contains/five ports 40 each of which serves two cylinders in row F and four cylinders in row G. I

The capacity of the pump may be varied by varying the number of rows of cylinders and it may be further varied by varying the number of cylinders in each row.

The pistons in each row of cylinders are urged inward during one-half revolution of the cylinder barrel by a thrust ring 4| which is arranged around the cylinder barrel eccentric thereto and is differentiated from the other thrustrings by adding as an exponent to its reference numeral 4| the reference letter of the row of pistons with which it is associated.

Each piston I6 is provided at its outer end with an enlarged head having beveled or arcuate outer and underfaces, and each thrust ring 4| has its inner facebeveled and in contact with the heads of the pistons in one of the circumferential rows, the head of each piston contacting a thrust ring upon a single point or spot arranged in row F, and the inner order between the ends thereof so that the piston has a uniform bearing in its cylinder and undue and irregular wear of the cylinder wall is avoided.

When the pump is delivering liquid under pressure, it hasan internal leakage or slip which consists primarily of small volumes which pass across the bridge from the discharge port to the intake port and other small volumes which pass along the pintle and escape from the ends of the cylinder barrel and through the drain channel 3|. The pump also has an apparent slip which is due primarily to compression of the liquid and deflection of certain pump parts.

The slip of a pump varies in accordance with variations in both the pressure and the tempera-,

ture of the liquid for the reason that, with a given film thickness, the film will move more rapidly under a high pressure than under a low pressure and, due to variations in the viscosity of the liquid, the film will flow more readily and rapidly when hot than when cold.

When the pump is in operation, pressure prevails in the lubricating film between the cylinder barrel and the pintle, as previously explained, and this pressure acts upon the projected areas of the tapered coacting surfaces of the cylinder barrel and the pintle and urges the cylinder barrel toward the small end of the pintle with a force which varies as the pump pressure varies, thereby tending to increase the clearance toward the large end of the pintle by a force equal to the sum of the lateral components of the pumping forces transmitted through all 'of the pistons, thereby tending to decrease the clearance between thecylinder barrel and the pintle and decrease the slip of the pump.

, In order to keep the slip of the pump as low as possible and thereby maintain pump delivery substantially constant, the pump parts are so proportioned that the sum of the above mentioned forces which urge the cylinder barrel toward the large end of the pintle exceed the total force which tends to move the cylinder barrel toward the small end of the pintle.

This excess force urges the cylinder barrel toa Vii ever more firmly against the pintle as pump pressure increases, thereby reducing thethickness of the lubricating film in response to an increase in pressure and also in response to a decrease in the viscosity of the liquid.

The slip of the pump is thus maintained at the minimum consistentwith sufficient lubrication at all operating pressures and temperatures, thereby keeping the net delivery of the pump approximately constant.

The thrust rings 4| are arranged within and restrained from radial or axial movement by a rotatable drum 42 which is supported within acradle 43 upon two ball bearings 44 and 45 arranged, respectively, at its front and its rear ends and carried by the cradle 43.

The thrust rings 4| are held against movement relative to the drum 42 and are arranged therein iii eral rings in contact with each other. All of the thrust rings are thus held against movement relative to the drum 42.

The filler block 41 is engaged upon its front end by an annular bearing block 48 which is fitted within thedrum 42 and has the outer race of the bearing 44 fitted within its frontend.

The bearing 44 is of the radial thrust type and has its inner race fitted upon the hub of an end plate 49 which is fitted within the front end of the cradle 43 and retained in position therein by a threaded ring 50 which is threaded into the front end of the cradle 43.

The drum 42, the thrust rings 4|, the filler block 41 and the bearing block 48 combine to form a thrust member which urges the pistons inward during rotation of the cylinder barrel and which is rotated upon the bearings 44 and 45 in synchronism with the cylinder barrel by frictional contact of the piston heads with the thrust rings 4|.

When the pump is delivering liquid, the axis of the drum 42 is ofiset from the axis of the cylinder barrel in order that the pistons may move outward during one-half of a revolution of the cylinder barrel to permit the cylinders to be filledwith liquid and in order that the pistons will be forced inward during the next half-revolution of the cylinder barrel to eject liquid from the cylinders.

This outward and inward movement of the pistons causes each piston head to move at a variable linear speed which varies in accordance with the distance between it and the axis of rotation of the cylinder barrel, while the thrust ring with which that piston head is in contact moves at a constant linear speed. Therefore, during one part of a revolution, each piston head moves faster than a given point on the thrust ring with which it is in contact and it moves slower than that point during another part of a revolution.

Since each piston head is in contact with its thrust ring at only a single point or spot which is offset from the piston axis, this variation in the relative linear speeds of the piston head and its thrust ring causes the piston head to roll along the thrust ring and the piston to rotate in its cylinder, thereby eliminating all sliding friction between the pistons and the thrust member and also avoiding the use of the heavy crossheads formerly employed upon the ends of pump pistons to eliminate sliding friction.

The stroke of the pump, or the length of the outward and inward movement of each piston, is proportional to the distance between the axis of the cylinder barrel and the axis of the thrust member. This distance may be fixed by securing the cradle 43 in a permanent position within the casing In, to thereby provide a pump having a fixed stroke and constant displacement, or the cradle 43 maybe adjustable, as 'shown in Fig. 2, to provide a pump having a variable displacement.

As shown in Fig. 2, the cradle 43 has a'suitable number of slide plates attached thereto and casing l0.

in contact with a corresponding number of stationary slide plates 52 which are carried by the The slide plates 5| and 52 permit the cradle to move transverse to the pintle axis in a horizontal direction but prevent it from moving transverse to the pintle axis in any other direction.

In actual practice, the pump is ordinarily provided with a hydraulically operated control for shifting the cradle 43 but, for the purpose of illustration, it is shown provided with an adjusting screw 53 which is fastened to the cradle 43 and has a handwheel 54 threaded thereon for manual adjustment of the pump.

The handwheel 54 is restrained from axial movement in one direction by the end of its hub abutting a plate 55, which is fastened to the casing l0 and closes an opening 56 therein, and it is restrained from axial movement in the op posite direction by one or more bearing plates 51 which are fastened to the plate 55 and extend into an annular groove 58 formed in the hub of the wheel.

When the cylinder barrel I4 is rotated in the direction of the-arrows and the thrust member has its axis offset toward the left from the axis of the cylinder barrel as shown in Fig. 2, the pistons in the lower half of the cylinder barrel will move outward to permit their cylinders to be filled With liquid through the pintle port 20,

the pistons in the upper half of the cylinder the stroke and the volumetric delivery of the pump until the cradle arrives at its central or neutral position, that is, when the axis of the thrust member coincides with the axis of the cylinder barrel, at which time pump delivery is zero.

Further movement of the cradle 43 toward the right will cause the pump to be reversed, that is, to discharge through the port and at a rate corresponding to the distance which it is moved from its central or neutral position. The pump may also be reversed byreversing the direction of rotation of the cylinder barrel, in which case the pump will discharge through'the pintle port 20 when the cradle is at the left of its neutral position and through the pintle .port l9 when the cradle is at the right of its neutral position.

When the cylinder barrel is being rotated at its normal operating speed, centrifugal force tends to move the pistons on the intake side outward, but at low speeds this is not always to be relied upon for supplying liquid to the cylinders which are positively and completely filled by either delivering liquid thereto under a low pressure or by providing mechanical means for positively retracting the pistons.

Liquid may be supplied to the cylinders by an ordinary type of gear pump which is arranged in the front head and-has its driving gear 59 fixed upon the drive shaft 32 and its driven gear 60 arranged upon a stub shaft 6| carried by the front head I The gear pump provides an auxiliary source of pressure liquid for operating controls and the like, and it may be incorporated in the pump for this purpose even when mechanical means are provided for retracting the pistons.

" rings 62 one of which is arranged alongside eachcircumferential row of pistons and in contact with the under face of each piston head in that row. The retraction rings are flexible and resilient in order that each ring may deflect slightly into a non-circular shape as the piston heads in contact therewith move relatively to the thrust ring with which they are in contact and yet maintain a continuous outward pressure on each piston head.-

Each retraction ring 62 is engaged at its front edge by a flat pressure ring 63 which is urged rearward by a number of springs 64 to keep the rear edge of the retraction ring in contact with the under faces of all of the piston heads in its row of pistons.

The springs 64 react against the rear end of the bearing block 48 and are-arranged in recesses which are formed in the front end of the filler block 41 and arranged in concentric circles.

The springs 64 in the recesses in the innermost circle act directly upon the front'pressure ring 63 a but the other springs 64 act upon the other pressure rings through push rods 65 which extend through the filler block 41 and through one or more of the thrust rings 4|, the push rod in engagement with one pressure ring being of a different length than the push rod in engagement with any other pressure ring.

The retraction rings 62 hold the piston heads 7 in contact with the thrust rings and thus positively move the pistons on the intake side of the pump outward and enable them to draw the liquid into their cylinders during each revolution of th cylinder barrel.

If the machine is to be employed as a pump, it may be provided with either a gear pump or with mechanical means for retracting its pistons, or with both. If the machine is to be employed as a motor, it does not require either a gear-pump or other that the net delivery therefrom is zero when that port is covered by one of the bridges 25*. or 25* during which time a part of the cylindersinward moving pistons.

Each of sections l, 2, 3, 4 and correspond toone cylinder of a five-cylinder pump, such as the pump shown in my Patent No. 1,619,200, and if all of the cylinders in each section opened to a pintle port at the same time, the bridge reactions and the resultant noise would be the same'as in a prior pump of the same capacity."

However, the cylinder ports are so arranged that but one cylinder port opens to a pintle port at any given instant, thereby keeping the bridge reactions and the resultant noise at a minimum.

- equal parts.

The arrangement of cylinder ports to produce this result is best shown in Figs. 4 and 5, Fig. 4 being a schematic developed view of the outside of the pintle I 3 with the cylinder ports superimposed thereon, and Fig. 5 beinga similar but simplified view showing only two rows of cylinder ports.

Referring first to Fig. 5, it will be noted that there are ten cylinder ports arranged in two circumferential rows of live ports each and that .each of sections I, 2, 3, 4 and 5 contain two ports one of which is arranged in the outer row and the other in the inner row.

If the two-ports in each section were arranged in alinement axially of the pintle, both would open to a pintle port at the same instant, that is, the pump would still be a single phase pump even though it is provided with two cylinder ports in each section.

If all of its ports were equally spaced, that is, if the ports in one row were advanced ahead of the ports in the otherrow by one-half the angular distance between the centers of adjacent ports, the effect would be to produce a ten section pump which would still be single phase and have the added disadvantage that one port would open to the pintle-intake port at the same instant that another port opened to the pintle discharge port, and the total bridge reactions would be as great as a five-section single phase pump of the same volumetric capacity.

In the present invention, however, the cylinder ports in one section open successively to one pintle port, immediately thereafter the cylinder ports in another section open successively to the other pintle port, and no two cylinder ports open to any pintle port at any given instant.

This is accomplished by positioning the cylinder ports in each succeeding row such a small angular distance behind the corresponding cylinder ports in the preceding row that all of the cylinder ports in one section have their leading ends, or the ends which first open to a pintle port, arranged within one-half of the section angle and, in order that the bridge reactions may be distributed uniformly throughout each revolution of the cylinder barrel, the cylinder ports are so positioned that the leading end of each cylinder port in each succeeding row is spaced from the leading end of the corresponding cylinder port in the preceding row by an angular distance equal to one-half the section angle divided by the number of rows of ports.

For example, the pump shown has its cylinder barrel divided into five .equal sections each of cylinder barrel had two rowsof cylinder ports as shown in Fig. 5, each sectionwould contain two ports one of which would be spaced from. the other port'by an angular distance determined by dividing one-half of the section angle into two Hence,' the two'ports in'each section would be spaced 18 apart to split the phase of the pump.

The ports in one section of- Fig. 5 are practically the same asthe ports in any other section but, in order to differentiate therebetweenQ the ports in the outer and inner rows have been designated, respectively, by the letters A and B added to the number of the section in which the same are arranged.

With the cylinder'ports arranged as shown in Fig. 5, rotation of the cylinder barrel will cause the outer and inner ports in one section to open successively to one pintle port and then the outer -which extends through an angle of 72. If the and inner ports in another section to open successively to another port; As shown, all ports in sections 2 and 3 and port I in section I are open to the pintle intake port 20, all ports in sections land and port I in section I are open to the pintle discharge port l9.

Assuming that the cylinder barrel is rotating in the direction of the arrow, port I has just opened to the port I9 and port I will open next so that the shock caused by the opening of port I has passed before the shock caused by the opening of port I occurs.

After port I opens to pintle port I9, ports 4} and 4 will open successively to pintle port 20, then ports 2* and 2 will open successively to pintle port I9, then ports 5 and 5 will open successively to pintle port 20, then ports 3 and 3 will open successively to pintle port I9, and the ports in each section will continue in this manner to open successively and at uniform intervals first to one pintle port and then the otherbut no two ports will open at the same instant.

Consequently, the shocks and noise caused by the several cylinder ports opening to the pintle ports are distributed uniformly throughout each revolution of the cylinder barrel and are kept at a minimum. v

If the cylinder barrel is provided with a greater number of rows of piston ports, one-half of the section angle is divided into a correspondingly greater number of parts to. determine the split phasing of the pump. For example, if the cylinder barrel is provided with four rows of cylinder ports as shown in Figs. 1 to 4, each section will contain four cylinder ports which will be spaced 9 apart as shown in Fig. 4, this angular distance being determined by dividing one-half of the section angle by four.

With the cylinder ports arranged in this manner, all four ports in one section will open suecessively to one pintle port and then all four ports in another section will open successively to another pintle port but no two pintle portswill open at any given instant.

Assuming that the ports are in the position shown in Fig. 4 and that the cylinder barrel is rotating in the direction of the arrow, port 31 in section I has just opened to the pintle port I9, ports 38, 39 and 40 in section I will open successively to the port I9 as the cylinder barrel continues to rotate, and port 40 in section I will open to port I9 before port 31 in section 4 opens to pintle port 20.

Immediately thereafter, the cylinder ports in section 4 will open successively to the pintle port 20 and then the cylinder ports in section 2 will open successively to the pintle port I9.' The cylinder ports in succeeding sections will open successively to the two pintle ports alternately and,

since the sections are equally spaced and since the cylinder ports in each section are spaced the same angular distance apart, the bridge reactions are distributed uniformly throughout each revolu tion of the cylinder barrel.

A pump or motor constructed in accordance with the present invention is eflicient in operation and will operate quietly even when made in large sizes.

The pump described herein is susceptible of various modifications without departing fromthe scope of the invention as hereafter claimed.

The. invention is hereby claimed as follows:

1. A split phase pump, comprising a valve member having intake and discharge ports, a rotatable cylinder member bearing upon said valve member and provided with a plurality of cylinders having ports to communicate with said valve ports alternately as said cylinder member rotates and so arranged that but one cylinder port opens to a valve port at any given instant and that a plurality of cylinder ports open successively to one of said valve ports and then another plurality of cylinder ports open successively to the other valve port, pistons arranged in said cylinders, and means for causing reciprocation of said pistons during rotation of said cylinder member.

2. A split phase pump, comprising a valve member having intake and discharge ports, a'rotatable cylinder member bearing upon said valve member and provided with a plurality of cylinders having ports to communicate with said valve tates, said cylinder ports being arranged in a plurality of circular rows and so positioned in respect to each other that a plurality of cylinder ports open successively tov one valve port and then another plurality of cylinder ports open successively to the other valve port but only one cylinder port opens to a valve port at any given instant, pistons arranged in said cylinders, and means for causing reciprocationof said pistons during rotation of said cylinder member.

3. A split phase pump, comprising a valve member having intake and discharge ports, a rotatable cylinder member bearing upon said valve member and provided with a plurality of cylinders having ports to communicate with said valve ports alternately as said cylinder member rctates, said cylinder ports being arranged in a plurality of circular rows and so positioned in respect to each other-that but one cylinder port opens to .a valve port at anygiven instant and that a plurality of cylinder ports open successively to one of said valve ports and then another plurality of cylinder ports open successively to the other valve port, pistons arranged in said cylinders, and means for causing reciprocation of said pistons during rotation of said cylinder member.

4. A split phase pump, comprising a valve member having intake and discharge ports, a rotatable cylinder member bearing upon said valve member and provided with a plurality of cylinders having ports to communicate with said valve ports alternately as said cylinder member rotates and arranged irra pluralityof circular rows with a port in one row forming with a port'in each of the other rows a group of ports-which have the leading ends thereof arranged within one-half or less of the angular distance between adjacent groups and open successively to said valve ports as said cylinder member rotates, pistons arranged in said cylinders, and means for causing reciprocation of said pistons during rotation of said cylinder member.

5. A split phase pump, comprising a.valve member having intake and discharge ports, a roports arranged in said cylinder member with a plurality of cylinders communicating with a sin-.

cylinder ports to communicate with said valve ports alternately as said cylinder member rotates, said cylinder ports being arranged in a plurality of circular rows and so positioned in respect to each other that a plurality of. cylinder ports open successively to one valve port and then another plurality of cylinder ports open successively to the other valve port but only one cylinder port opens to a valve port at any given instant, a greater number of cylinders than cylinder ports arranged in said cylinder member with a plurality of cylinders communicating with a single cylinder port, pistons arranged 'in said cylinders, and means for causing reciprocation of said pistons during rotation of said cylinder member. i

'7. A split phase pump, comprising a valve member having int ake and discharge ports, a rotatable cylinder member bearing upon said valve member and provided with a plurality of cylinder ports to communicate with saidvalve ports alternately as saidcylinder member rotates, said cylinder ports being arranged in a plurality of circular rows and so positioned in respect to each other that but one cylinder port opens to a valve port at any given instant and that a plurality of cylinder ports open successively to one of said valve ports and then another plurality of cylinder ports open successively to the other valve port, a greater number of cylinders than cylinder ports arranged in said cylin-' der member with a plurality of cylinders communicating with a single cylinder port, pistons arranged in said cylinders, and means for causing reciprocation of said pistons during rctation of said cylinder member.

8. A split phase pump, comprising a valve 'member having intake and discharge ports, a

rotatable cylinder member bearing upon said valve member and provided with a plurality of cylinder ports to communicate with said valve ports alternately as said cylinder member rotates and arranged in a plurality of circular rows with a port in one row forming with a port in each of the other rows a group of ports which have the leaifing ends the'recf arranged within one-half or less of the angular distance between adjacent groups and open successively to said valve ports as said cylinder member rotates, a greater number of cylinders than cylinder ports arranged in said cylinder member with a plurality of cylinders communicating with a single cylinder port, pistons arranged in said cylinders, and means for causing reciprocaticn of said pistons during rotation of said cylinder member 9. A pump, comprising a pintle tapering toward its front end and provided with intake and discharge ports and passages, a cylinder barrel fitted upon said pintle to rotate thereon. and provided with cylinder ports to register. with said pintle ports alternately as said cylinder barrel rotates, radial cylinders arranged in' said cylinder barrel in communication with said cylinder ports, a piston fitted in each cylinder to reciprocate therein and provided with a beveled outer end, a thrust member arranged around said cylinder barrel eccentric thereto and provided with a beveled face in contact with the outer end of each piston only at a point forward of the'piston axis whereby rotation of said cylinder barrel will cause said member to transmit forces to said pis-' tons to operate the same and the lateral components of said forces will 'urge said cylinder barrel toward the large end of said pintle with a force proportional to pump pressure, and means for rotating said cylinder barrel.

10. A pump, comprising a pintle tapering toward its front end and provided with intake and discharge ports and passages, a cylinder barrel I fitted upon said pintle to rotate thereon and provided with cylinder ports to register with said pintle ports alternately as said cylinder barrel rotates, radial cylinders arranged in said cylinder barrel in communication with said cylinder ports, a piston fitted ineach cylinder to reciprocate therein and provided with a beveled head upon its outer end, a thrust member arranged around said cylinder barrel eccentric thereto and'provided with a beveled face in contact with the head of each piston only at a point forward of the piston axis whereby rotation of said cylinder barrel will cause said member to transmit forces to said pistons to operate the same and the lateral components of said forces will urge said cylinder barrel toward the large end of said pintle with a force proportional to pump pressure, means for rotating said cylinder barrel, and means engaging said piston heads upon the under sides thereof to urge the same outward during rotation of said cylinder barrel.

11. A pump, comprising a pintle tapering toward its front end and provided with intake and discharge ports and passages, a cylinder barrel fitted upon said pintle to rotate thereon and provided with cylinder ports to register with said pintle ports alternately as said cylinder barrel rotates, radial cylinders arranged in said cylinder barrel in communication with said cylinder ports, a piston fitted in each ,cylinder to reciprocate therein and provided with a beveled outer end, a rotatable thrust member arranged around said cylinder barrel eccentric thereto and provided with a beveled face in contact with-the outer end of each piston only at a point forward of the piston axis whereby rotation of said cylinder barrel will cause said member to transmit forces to said pistons to operate the same and the lateral components of said forces will urge said cylinder barrel toward the large end of said pintle with a force proportional to pump pressure, means for supporting said thrust member, and means for rotating said cylinder barrel.

12. A pump, comprising a pintle tapering toward its front end and provided with intake and discharge ports and passages, a cylinder barrel fitted upon said pintle to rotate thereon and provided with cylinder ports to register with said pintle ports alternately as said cylinder barrel rotates, radial cylinders arranged in said cylinder barrel in communication with said cylinder ports, a piston fitted in each cylinder to reciprocate therein and provided with a beveled head upon its outer end, a rotatable thrust member arranged around said cylinder barrel eccentric thereto and provided with a beveled face in contact with the headof each piston only at a point forward of the piston axis whereby rotation of said cylinder barrel will cause said member to transmit forces to said-pistons to operate the same and the lateral components of said forces will urge said cylinder barrel toward the large end of said pintle with a force proportional to pump pressure, means for supporting saidthrust member, means for rotating said cylinder barrel, and means engaging said piston heads upon the under sides thereof to urge the same outward during rotation of said cylinder barrel.

13. A pump, comprising a pintle tapering toward its front end and provided-with intake and discharge ports and passages, a cylinder barrel fitted upon said pintle to rotate thereon and provided with cylinder ports to register with said pintle ports alternately as said cylinder barrel rotates, radial cylinders arranged in said cylinder barrel in communication with said cylinder ports, a piston fitted in each cylinder to reciprocate therein and provided with a beveled head upon its outer end, a rotatable thrust member arranged around said cylinder barrel eccentric thereto and provided with a beveled face in contact with the head of each piston only at a point forward of the piston axis whereby rotation of said cylinder barrel will cause said member to transmit forces to said pistons to operate the same and the lateral components of said forces will urge said cylinder barrel toward the large end of said pintle with a force proportional to pump pressure, means for rotating said cylinder barrel, resilient members engaging said piston heads upon the under sides thereof to urge the same outward during rotation of said cylinder barrel, and means for urging each resilient member toward the piston heads engaged thereby. 14. A pump, comprising a pintle tapering toward its front end and provided withintake and discharge ports and passages, a cylinder barrel fitted upon said pintle to rotate thereon and provided with cylinder ports so arranged that but one cylinder port opens to a pintle port at any given instant and a plurality of cylinder ports opensuccessively to one pintle port and then another plurality of cylinder ports open successively to the other pintle port, radial cylinders arranged in said cylinder barrel in communication with said cylinder ports, a piston fitted in each cylinder and provided with a beveled outer end, a thrust member arranged around said cylinder barrel eccentric thereto and provided with a beveled face in contact with the outer end of each pistononly at a point forward of the piston axis whereby rotation of said cylinder barrel will cause said member to transmit forces to said pistons to operate the same and the lateral components of said forces will urge said cylinder barrel toward the large end of said pintle with a force proportional to pump pressure, and means for rotating said cylinder barrel.

15. A pump, comprising a pintle taperingtoward its front nd and provided with intake and discharge ports and passages, a cylinder barrel fitted upon said pintle to rotate thereon and provided with cylinder ports so arranged that but one cylinder port opens to a pintle port at any given instant and a plurality of cylinder ports open successively to one'pintle port and then another plurality of cylinder ports open successively to the other pintle port, radial cylinders arranged in said cylinder barrel in communication with said cylinder ports, a piston fitted in each cylinder and provided with a beveled head upon its outer end, a thrust member arranged around said cyl-. inder barrel eccentric thereto and provided with a beveled face in contact withthe head of each piston only at a point forward of the piston axis whereby rotation of said cylinder barrel will cause said member to transmit forces to said pistons to operate the same and the lateral components of said forces will urge said cylinderbarrel toward the large end of said pintle with a force proportional to pump pressure, means for rotating said cylinder barrel, and means engaging said piston heads upon the under sides thereof to urge said pistons outward during rotation of said cylinder barrel.

16. A pump, comprising a pintle tapering toward its front end and provided with intake and discharge ports and passages, a cylinder barrel fitted upon said pintle to rotate thereon and provided with cylinder ports so arranged that but one cylinder port opens to a pintle port at any given instant and a plurality of cylinder ports open successively to one pintle port and then another plurality of cylinder ports open successively to the other pintle port, radial cylinders arranged in said cylinder barrel in communication with said cylinder ports, a piston fitted in each cylinder and provided with a beveled outer end, a rotatable thrust member arranged around said cylinder barrel eccentric thereto and provided with a beveled face in'contact with the outer end of each piston' only at a point forward of the piston axis whereby rotation of said cylinder barrel will cause said member to transmit forces to said pistons to operate the same and the lateral components of said forces will urge said cylinder barrel toward the large end of said pintle with a force proportional to pump pressure, means for rotating said'cylinder barrel, and means for supporting said thrust member.

1'7. A pump, comprising a pintle tapering toward its front end and provided with intake and discharge ports and passages, a cylinder barrel fitted upon said pintle to rotate thereon and provided with a plurality of cylinder ports arranged in a plurality of circumferential rows with a port in one row forming with a port in each of the other rows a group of ports which have the leading endsthereof arranged within one-half or less of the angular distance between adjacent groups and open successively to said pintle ports as said cylinder barrel rotates, radial cylinders arranged in said cylinder barrel in communication with said cylinder ports, a piston fitted in each cylinder and provided with a. beveled outer end, a thrust member arranged around said cylinder barrel eccentric thereto and provided with a beveled face in contact with the outer end of each piston only at a point forward of the piston axis whereby rotation of said cylinder barrel will cause said member to transmit forces to said pistons to operate the same and the lateral components of said forces will urge said cylinder. barrel toward the large end of said pintle with a force discharge ports and passages, a cylinder barrel.

fitted upon said pintle to rotate thereon and provided with a plurality of cylinder ports arranged in a plurality of circumferential rows with a port in one row forming with a port in each of the other rows a group of ports which have the leading, ends thereof arranged within one-half or less of the angular distance between adjacent groups and open successively to said pintle ports as said cylinder barrel rotates, radial cylinders arranged in circumferential rows in said cylinder barrel with a plurality of cylinders in each of a plurality of rows communicating with each of said cylinder ports, a piston fitted in each cylinder and provided with a beveled outer end, a thrust, member arranged around said cylinder barrel eccentric thereto and provided with a beveled face in contact with the outer end of each piston only at a point forward of the piston axis whereby rotation of said cylinder barrel will cause said member to'transmit forces to said pistons to operate the same and the lateral components of said forces will urge said cylinder barrel toward the large end of said pintle with a force proportional to pump pressure, and means for rotating said cylinder barrel.

19. A pump, comprising a pintle tapering toward its frontend and provided with intake and in said cylinder barrel in communication with said cylinder ports, a piston fitted in each cylinder and provided with a beveled head upon its outer end, a thrust member arranged around said cylinder barrel eccentric thereto and provided with a beveled face in contact with the head of each piston only at a point forward of the piston axis whereby rotation of said cylinder barrel will cause said member to transmit forces to said pistons to operate the same and the lateral components of said forces will urge saidcylindenbarrel toward the large'end of said pintle with a force proportional to pump pressure, means for rotating said cylinder barrel, and means engaging said piston heads upon the under sides thereof to urge said pistons outward during rotation of said cylinder barrel.

20. A pump, comprising a pintle tapering toward its front end and provided with intake and discharge portsand passages, a cylinder barrel fitted upon said pintle to rotate thereon and provided with a plurality of cylinder ports arranged in a plurality of circumferential rows with a port in one row forming with a port in each of the other rows a group of ports which munication with said cylinder ports, a piston fitted in each cylinder and provided with a beveled. outer end, a rotatable thrust member arranged around said cylinder barrel eccentric thereto and provided with a beveled face in con-- tact with the outer end of each piston only at a point forward of the piston axis whereby rotation of said cylinder barrel will cause said member to transmit forces to said pistons to operate the same and the lateral components of said forces will urge said cylinder barrel toward the large end of said pintle with a force proportional to pump pressure, means for rotating said cylinder barrel, and means for supporting said thrust member.

WALTER FERRIS. 

